Movable jetty



2 Sheets-Sheet 1.

N E D R N A V T R MOVABLE JETTY.

No. 309,264 Patented Dec. 16, 1884.

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ROBERT T. VAN NORDEN, OF SAN FRANCISCO, CALIFORNIA.

MOVABLE JETTY.

EPECIFICATION forming part of Letters Patent No. 809,264, dated December16, 1884.

Application filed June 11, 1884.

To all whom, [It may concern:

Be itknown that I, ROBERT T.VAN NORDEN, a citizen of the United States,residing at San Francisco, in the county of San Francisco and State ofCalifornia, have invented certain new and useful Improvements in MovableJetties, of which the following is a specification.

My invention relates to improvements in movable or floating jetties, or\vingdams; and the object of my invention is to provide a device wherebythe channels and bars of rivers and estuaries may be deepened by theaction of the current of outflowing water. This obj ect I accomplish bymeans of the device illustrated in the accompanying drawings, in which-Figure 1 is a plan view showing my improved jetty or wing-dam inposition. Fig. 2 is a side view of the same. Fig. 3 is afront view. Fig.4 is a plan view illust *ating a modification.

Similar letters of reference are used to indicate like parts throughoutthe several figures.

A represents the hull of any suitablevcssel, ship, or scow, to which thejetty or wingdains are attached.

B is a short substantial bowsprit, and O O are the cat-heads projectingfrom the port and starboard bows.

The movable jetty or wing-dams D D are composed of planking or sheetmetal suit-ably backed, braced, and stayed, and are secured in an edgewise or vertical position in any suitable manner to the bow orcut-water of the vessel by either hinges or bolts; and the rear edges orends of these j etty-boards are beveled off, as shown in Fig. 2, inorder to conform to the degree of rake or inclination given to the bowor stem of the vessel. These jetty-boards project forward from the bowof the vessel in a diverging manner, or at an angle of, say, aboutthirty degrees, with a fore'and-aft line drawn through the center of thevessel. The forward lower ends or corners of the floating wing-dams ormovable jetties are given an inward curve, warp, or wind, as shown, inorder to counteract the tendency of the bow to lift up, caused by thepressure of the increased volume of water produced by the concentrationof the current between the converging jetty-boards, and thus the outeror forward (No model.)

ends of the movable jetty counteract upon or counterbalance the inner orrear end thereof. As the tendency of the descending current of water isto force the jetty-boards farther apart, I connect each side board bybraces E E, which are connected to the bowsprit of the vessel, whileother braces, F F, extend backward from the said jetty side boards tothe cat-heads O O. The jetty-boards can, however, be adjusted as towidth and pitch or angle, as desired.

In the modification shown in Fig. 4c the general construction and formof the jetty is the same, with the exception that two vessels areemployed, one upon each side of the triangle formed by the j ettyboardsand connectd thereto by suitable braces. This device is intended moreparticularly for use in rivers and at the mouths thereof, or in anyother place where there is a' current setting continuously in onedirection 5 and in operation the vessel is steamed or towed up stream,or is allowed to drop down from above onto the upper side of the sandbar or flat which is intended to be operated upon. The vessel is thenmade fast by anchorage, or, when in a narrow stream, by spring-linesleading to the shore, and is held in position with the flaring mouth ofthe jetty pointing up stream. The body of water which now enters themouth of the jetty will be concentrated as it approaches the apex of thetriangle, and as the jetty-boards project high enough out of the waterto prevent any overflow or wash, all the water so concentrated will bedirected downward beneath the keel of the vessel and a strong currentwill be produced at this point, sufiicient to flash out or wash away thesand or mud and leave a channel of considerable depth beneath thevessel.

NVhen the channel hasibeen cut as deep as the force of the descendingcurrent will permit of, the vessel is then lowered down the stream untilthe end of the channel so produced has been reached, when the vessel isagain made fast, and the whole operation is repeated.

From the foregoing it will be seen that I am enabled to provide afloating wing-dam or movable jetty which is of cheap and simpleconstruction, and provide a means whereby sand bars and other similarobstructions in -IOO rivers and estuaries may be easily and quickly inthe Water and connected at their rear ends, 10

removed and the channel-way deepened by said jetty being secured to oneor more vessels,

the direct action of a concentrated body of substantially as and for thepurpose described.

Water directed upon the obstruction. In testimony that I claim theforegoing I 5 Havingthus described my invention, what I have hereuntoset my hand and seal.

claim, and desire to secure by Letters Patent, 7 ROBERT T. VAN NORDEN.[u s] is-- Witnesses:

A movable jetty consisting of two diverging WILMER BRADFORD,

jetty-boards or Wing-dams, D D, set vertically G. W. M. SMITH.

